We call this kind of eye a compound eye, and because all the little lenses point in different directions, animals that have them are very good at detecting movement – especially of big things ...

"Every animal does something special ... the object and stop it from moving past the object. But insect movement is completely different. "An insect walking is like the little kid in 'A Christmas ...

We must not forget that faster movement observed against a background of slower moving individuals is rather easy to perceive for most animals. In fish, this doesn't only happen through vision ...